The inventive subject matter relates to power conversion circuits and methods and, more particularly, to inverter apparatus and methods.
Rectifier and inverter circuits are used in uninterruptible power supply (UPS) systems, motor drives and other power apparatus. Some inverters and rectifiers have a multilevel architecture that uses multiple commutation states. Various multilevel inverter and rectifier circuits are described, for example, in U.S. Pat. No. 5,361,196 to Tamamachi et al., U.S. Pat. No. 6,031,738 to Lipo et al., U.S. Pat. No. 6,795,323 to Tanaka et al., U.S. Pat. No. 6,838,925 to Nielsen, U.S. Pat. No. 7,145,268 to Edwards et al. and U.S. Pat. No. 7,573,732 to Teichmann et al.